Trap-neuter-return, commonly referred to as TNR, is the only scientifically supported humane method for managing feral and stray cat populations. It involves trapping cats, taking them to a veterinarian for spaying or neutering, vaccinations, and ear tipping for identification. The cats are returned to their original territory, where a caretaker provides food and shelter.

TNR improves the lives of feral cats, improves their relationships with the people who live near them, and decreases the size of colonies over time. TNR is the preferred method for managing free-roaming cat populations and is supported by city shelters and rescues across the Bay Area and animal advocacy groups throughout the United States.

Trap-neuter-return is the only method proven to be humane and effective at controlling outdoor cat population growth. Using this technique, all the cats in a colony are trapped, vaccinated, sometimes treated for select injury or illness, neutered, ear tipped for identification, and then returned to their colony. The goal of any TNR program is to maximize the quality of life for the cats and to eliminate the existing colony over time through attrition. Additional benefits of TNR include:

• Fewer kittens are born outside

• Fewer sick and injured cats

• Reduction in common nuisance behaviors like fighting, roaming, mating, and spraying

• Colony size is gradually reduced without the need for euthanasia

• Shelters and rescues take in fewer surrendered cats

• Euthanasia rates go down

The vacuum effect occurs when community cats are permanently removed from their home colonies. The cats may have been killed or removed by people, or any other means. The result is a temporary dip in number of cats at the colony. This population dip is only temporary. The initial group of cats lived in that location because there were resources such as shelter, food, and water. Though the cats are gone the location is still desirable to other cats and therefor a vacuum is created. This vacuum inevitably attracts other cats and wildlife, thus filling the void that the removed cats created. The vacuum effect is a natural phenomenon that not only impacts cat colonies but can be observed in other animal populations.

TNR programs, rather than removing cats and forcing a vacuum, ends the breeding cycle of the cats altogether. Through TNR, community cats are humanely trapped, spayed or neutered, vaccinated, ear tipped to show they are fixed, and returned to their outdoor homes where they continue to lead full, healthy lives.

More information about the vacuum effect can be found online:

• Alley Cat Allies, The Vacuum Effect

• Alley Cat Allies, All About the Vacuum Effect (YouTube video)

• Swarbrick, H., & Rand, J. (2018). Application of a Protocol Based on Trap-Neuter-Return (TNR) to Manage Unowned Urban Cats on an Australian University Campus. Animals : an open access journal from MDPI, 8(5), 77.

A stray cat is a domestic cat that strayed from home and became lost or was abandoned. Because a stray cat was once a companion pet, they usually can be re-socialized and placed in an adoptive home.

A feral cat is a domestic cat that has reverted to a wild state after living outside, or more likely, a cat that was born to a stray or feral mother and had little or no human contact. Adult feral cats are very difficult to tame and are not usually ready for adoption. They live in family groups called colonies that form near a source of food and shelter.

There are some key markers and attributes that may help you distinguish between the two.

• Stray cats might

  • approach you outside

  • approach food right away that you put down and eat in front of you

  • meow at you and be vocal

  • look dirty and unkempt

  • be seen during all hours of the day

  • be alone

• Feral cats might

  • not approach you or will run around when spotted

  • wait until you leave to eat

  • be silent and will not meow at you

  • appear well groomed

  • only be seen at dusk, nighttime, and dawn

  • be seen in packs and with other cats

Community cat is a broad term used to classify a range of cats. Most often people think of a community cat as a feral cat. Feral cats are not socialized they do not want to live indoors with people as pets. Feral cats should not be taken to shelter and instead should be fixed and remain outside. There are other community cats that may wish to live indoors.

Many community cats have caretakers and guardians that love and care for them deeply. They may not be able to pet the cat or even get too close but the human-animal connection is still there. To suggest that caretakers do not provide compassion and love to their colony cats is not true.

Critics of TNR often argue that every cat deserves the safety and love of an indoor home and that the life of a free-roaming cat is dangerous. While some aspects of this argument may be true, it is simply not practical nor feasible to remove all cats from their outdoor homes and this pertains to friendly adults and kittens as well.

We believe that TNR is a form of harm reduction with the explicit goal of immediately improving the lives of the cats we encounter. When there is an overabundance of need and only a limited amount of resources we must make the difficult decisions that will result in the biggest impact.